1. Field of the Invention
The present invention relates to a liquid container and a cap for sealing off a supply port of the liquid container. More particularly, the present invention relates to an ink tank for use with an ink jet recording head in which an ink is ejected for recording, and a cap for sealing off an ink supply port of the ink tank.
2. Description of the Related Art
There is known a combination of a liquid ejection recording head (ink jet recording head) in which a liquid (taking an ink as an example in the following description) is ejected for recording, and a liquid container (ink tank) for containing the ink supplied to the recording head. From the viewpoint of operating cost, the combination has been hitherto often practiced such that the ink tank is attached to the recording head in a detachable manner. In the case of manufacturing the recording head and the ink tank detachably fitted to each other, it is required that the ink tank be attached to the recording head with an easier operation or a simpler mechanism without causing troubles when attached to and detached from the recording head.
In Japanese Patent Laid-Open No. 8-58107, No. 8-224883 and No. 8-276601, for example, the assignee discloses an ink tank which has an ink supply port for supplying a recording ink contained therein to the outside through the same and which is inserted into an opening of a box-shaped ink tank holder in a detachable manner, the ink supply port being communicated with an ink taking-in means of the ink tank holder when the ink tank is attached to the ink tank holder. In the ink tank, a slope is formed at an edge where a bottom surface, which faces a bottom wall of an opening of the ink tank holder when the ink tank is attached to the ink tank holder, crosses one end surface adjacent to the bottom surface. Further, a claw-like projection fitted to a slip-off check hole formed in the ink tank holder is provided on the one end surface, and a latch lever having a latch claw, which engages in an engagement hole formed in the ink tank holder, is provided on the other end surface in a flexibly supported manner. The invention disclosed in these patents is superior in coupling the ink tank and the recording head to each other, and is practiced in many ink tanks.
Meanwhile, to prevent an ink leakage through the ink supply port when the ink tank is handled alone (e.g., during a distribution process), a cap is usually attached to the ink supply port of the ink tank. In general, such a cap has a sealing member made of an elastic material for positively sealing off the ink supply port. The sealing member is provided on a surface of a cap body which has a rigidity, and hooks engaging with the ink tank are provided respectively on opposing surfaces of the cap body projected from the rigid surface. One of the opposing surfaces has a tab provided thereon which is pulled by the user at the time of removing the cap from the ink tank. When the user holds the ink tank and pulls the tab, the surface of the cap body including the tab provided thereon is elastically deformed so that the cap may be removed from the ink tank.
With a recent improvement in performance of an ink jet recording head, there is a tendency that many different kinds of inks are used interchangeably in the ink jet recording head. This tendency leads to a result that a material vulnerable to repeated bending is employed as the material of an ink tank body in some cases depending on the kinds of inks used. In trying to fabricate the ink tank, which as disclosed in the above-cited Japanese Patent Laid-Open No. 8-58107, etc. has a latch lever, using such a material, a risk has been found in that when the ink tank is handled in an unexpected way far from the normal one, e.g., when the user puts a finger between the ink tank body and the latch lever and applies a force to the finger in a direction of moving the latch lever away from the ink tank body, the latch lever may be detached from the ink tank body.
On the other hand, the following problem has been experienced with the cap of the ink tank. Because the surface of the ink body including the elastic sealing member provided thereon has a strong rigidity, a large force is required to disengage the hooks from the ink tank at the time of removing the cap from the ink tank. In addition, almost as soon as the hooks are disengaged, the cap is removed from the ink tank. Therefore, particularly when the ink tank has a small size, there is a risk that, depending on how the ink tank is held by the user, the ink may scatter through the ink supply port, or one or both of the ink tank and the cap may slip off and drop from the user""s hand.
The present invention has been made by the inventors with the view of addressing the above problems that have been experienced with an ink tank that is separable from a recording head. A first object of the present invention is to provide a liquid container and a cap-equipped liquid container in which a lever is protected without causing wasteful use of a space otherwise necessary for attaching the liquid container.
A second object of the present invention, which is to be realized in addition to the first object or alone, is to provide a cap capable of being easily removed by the user even when the cap is applied to a small-sized ink tank, and capable of reliably protecting an ink supply port.
To achieve the above objects, the present invention provides a liquid container comprising a lever having one end supported to an outer wall of a housing containing a liquid therein and the other end as a free end, the lever being elastically deformable, wherein the liquid container further comprises a projection provided in an area of the housing which is opposite to and away from the supported one end of the lever, the projection covering at least a part of a space between the free end of the lever and the housing in said area.
The lever provided on the liquid container is used in operation for attaching the liquid container to a holder or the like. According to the liquid container of the present invention, the projection covering at least a part of the area between the free end of the lever and the housing is provided at the above-defined location of the housing of the liquid container. With such a construction, which is easy to manufacture, it is possible to prevent an accidental external force from being exerted on the free end of the lever that is otherwise particularly easily subjected to an accidental external force. Further, since the projection is provided in the above-defined area of the housing, the projection will not interfere with the operation of attaching the liquid container to the holder or the like, and therefore wasteful use of a space necessary for attaching and detaching the liquid container is avoided.
The present invention also provides a cap-equipped liquid container comprising the above-described liquid container of the present invention and a cap fitted to the liquid container, the cap comprising an elastic sealing member for sealing off a supply port formed in the liquid container to introduce a liquid in the liquid container out of the liquid container, and a cap body on which the elastic sealing member is provided, wherein the cap body includes an engagement member engaging with the liquid container to hold the cap in place, and a tab disposed near the engagement member and used for removing the cap from the liquid container. A straight line connecting a projected end of the projection of the liquid container and a distal end of the tab is set to cross a movable range of the lever provided on the liquid container in which the lever is allowed to angularly move with elastic deformation thereof.
With the cap-equipped liquid container of the present invention, since the straight line connecting the projected end of the projection of the liquid container and the distal end of the tab of the cap is set to cross the movable range of the lever in which the lever is allowed to angularly move with elastic deformation thereof, the lever will not deform beyond the allowable range of elastic deformation even when an impact is accidentally exerted on the liquid container upon a fall, for example. Also, when the projected end of the projection of the liquid container and the distal end of the tab of the cap strike against a flat plane, the lever is elastically deformed until the free end thereof reaches the above straight line, thereby dampening an applied impact through the elastic deformation of the lever.
The present invention further provides a cap fitted to a liquid container having a supply port formed in a bottom wall thereof for supplying a liquid in the liquid container out of the liquid container, wherein the cap comprises a first latch member engaging with a first engagement member provided on one side wall of the liquid container; a second latch member engaging with a second engagement member provided on the other side wall of the liquid container opposite to the one side wall on which the first engagement member is provided; a bottom wall portion connecting the first engagement member and the second engagement member to each other and including an elastic sealing member provided thereon for sealing off surroundings of the supply port; and a tab provided near the first latch member to lie in a direction of extension of the bottom wall portion and used for removing and fitting the cap from and to the liquid container, a part of the bottom wall portion being able to elastically deform with application of an operating force for removing the cap from the liquid container.
With the cap of the present invention, the cap is fitted to the liquid container by engaging the first and second latch members respectively with the first and second engagement members provided on the opposing side walls of the liquid container. The elastic sealing member for sealing off the surroundings of the supply port of the liquid container is provided on the bottom wall portion connecting the first and second latch members to each other, and therefore the supply port is protected by the bottom wall portion. Also, since the tab used in the operation of removing the cap is provided near the first latch member to lie in the direction of extension of the bottom wall portion, the first latch member is first disengaged and the second latch member is then disengaged. In this connection, since a part of the bottom wall portion is able to elastically deform upon application of the operating force for removing the cap from the liquid container, a shock occurred upon opening the supply port of the liquid container is reduced and the cap can be easily removed without troubles.